elventu
Veteran Member
Joined: October 2018
Posts: 122
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Post by elventu on Dec 20, 2018 19:07:36 GMT -5
This night is the 2nd one with temperature below zero here, in the middle of central/northern adriatic coast of Italy. I'm used to cold weather, I lived for 36years in the alps, but my girlfriend and my friends from here are more used to "wet cold", like 3/10°C with high humidity... I'm just have return home with my dog after a dinner in a restaurant with them, they run to home due of the "cold" weather. On the other hand I'm killed by the wet cold they are used to, my bones ask me for hours in front of the wood stove I had in the alps after some hours in that conditions... 😶 In order to limit distortions of the parts, can't you add some steel reinforcements bolted to the plate? Not the best way to do it, but maybe it can do something to make the plate more rigid...? If someone is interested, I know that at my job they are used to work an aluminum alloy that don't warp for a customer that produces molds for plastic. I can't remember what alloy is, but I know that it is very good to machine and it have a high tensile strenght. Monday I ask for informations. I asked for that alloy. If someone is interested, is called "HOKOTOL". It is a kind of ergal, 7xxx aluminum series (7050 if I'm not wrong). It has a high tensile strenght, excellent machinability and thermal stability. I think it can be a good choice for turbine engines! |
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Post by Johansson on Dec 21, 2018 0:00:53 GMT -5
I´ll make a note of that for the future, thanks Elventu!
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monty
Senior Member
Currently being spanked by mother nature.......
Joined: September 2018
Posts: 400
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Post by monty on Dec 21, 2018 0:42:13 GMT -5
Any hole drilled on the side can be the cause of a warping, maybe hours after the machining. I have had some trouble in the past with 6082 (anticorodal) and expecially 7075 (ergal) making parts for a factory that make cigarette packing machine. Elventu,
I have worked with a lot of 7075. It's definitely not all created equal. It does indeed tend to move around and is also prone to stress corrosion cracking. Sometimes machined 7075 will fail from stress corrosion cracking just sitting on a shelf!! The key is to get good material for machining. The best stuff has been stretched to relieve the internal stress so it will not move. I have had good luck with 7075-T6511. The 511 or 51 suffix means the billet was stress relieved by stretching.
Monty
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elventu
Veteran Member
Joined: October 2018
Posts: 122
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Post by elventu on Dec 21, 2018 1:25:54 GMT -5
I don't remember what kind of suffix had the bar used for the various work i do in the past, but probably it is the same you mentioned as the best. I worked with some 7075 and 2017 alu expecially between 2008 and 2012, I worked in a factory where we do woodworking tools. Sometime better quality, sometime...not! 😶 Any hole drilled on the side can be the cause of a warping, maybe hours after the machining. I have had some trouble in the past with 6082 (anticorodal) and expecially 7075 (ergal) making parts for a factory that make cigarette packing machine. Elventu,
I have worked with a lot of 7075. It's definitely not all created equal. It does indeed tend to move around and is also prone to stress corrosion cracking. Sometimes machined 7075 will fail from stress corrosion cracking just sitting on a shelf!! The key is to get good material for machining. The best stuff has been stretched to relieve the internal stress so it will not move. I have had good luck with 7075-T6511. The 511 or 51 suffix means the billet was stress relieved by stretching.
Monty
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Post by Johansson on Dec 31, 2018 2:14:12 GMT -5
The last bits of work on JU-02 for this year, I got up early and spend a while in the workshop. First I centered the compressor cover around the wheel and drilled holes for 5mm dowels, earlier I used M5 screws but the diametrical fit was sloppy enough to allow the cover to misalign.  Then I welded the NGV´s properly, earlier I had just melted them in place without filler rod but now I added a bit more since I saw signs of a few hairline cracks in them. I will off course recheck the turbine clearance in case the welding has warped the NGV a little.  The suction line oil filter was also added, now I am filtering the oil both before and after the pump so I think the engine will be getting pretty clean oil from now on.  The 12v-24v converter is making the pump pretty noisy, on 24v battery power the pump is much quieter but it might be some switching noise perhaps. I´ll have a friend come over with an oscilloscope and check the output from the converter. I don´t mind the noise but I want to be sure that it isn´t harmful to the pump motor. Cheers and happy new year guys! /Anders |
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Deleted
Joined: January 1970
Posts: 0
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Post by Deleted on Dec 31, 2018 2:50:00 GMT -5
Hi Anders All looking like you soon be ready for another test  wishing every luck and a very happy new year Will be good to see the out put from the electric box, see if you getting 24 volt or some thing like ? All The Best Andy |
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Post by Johansson on Dec 31, 2018 4:06:52 GMT -5
Hi Anders All looking like you soon be ready for another test wishing every luck and a very happy new year Will be good to see the out put from the electric box, see if you getting 24 volt or some thing like ? All The Best Andy Hi Andy, Thanks! I return the wishes for your engine and new year. I am getting a stable 24v output but there might be spikes and stuff that won´t show up on the multimeter, so I´ll ask Olov to help me measure it. Cheers! /Anders |
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Deleted
Joined: January 1970
Posts: 0
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Post by Deleted on Jan 1, 2019 5:41:47 GMT -5
Hi Anders Good you are getting 24 volts, so many of these box's of sparks say one voltage and when you check you getting a little less Yep well worth checking, like you say could be something to do with how its switching Looking forward to testing video Andy |
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Post by Johansson on Jan 1, 2019 11:30:49 GMT -5
Hi Andy, Me too, I hope I have had enough of mishaps and troublesome systems now for a while. Test running the engine is fun but I am really eager to get it over with so I can start installing the engine in the bike, I will have to find new placements for most everything in the chassis so new pump brackets, a new battery box with space for the 12-24v converter etc etc. Lots of metal work ahead in other words, great news! Cheers! /Anders |
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Post by Johansson on Jan 2, 2019 8:49:04 GMT -5
I dropped off the compressor and two turbine rotors at my local turbo company today, he will check the old turbine for damage and balance a new rotor set for JU-02. A good start for 2019 indeed!
I've made sort of a new year promise to myself to stop slacking around and find more time to work on the bike, I can easily do 2-3 hours every weekend morning when the rest of the family is asleep.
Cheers!
/Anders
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Post by Johansson on Jan 3, 2019 2:53:38 GMT -5
The beginning of an intake bellmouth/air screen holder.  Cheers! /Anders |
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Post by Johansson on Jan 4, 2019 2:07:35 GMT -5
Some progress with the intake bellmouth, I will fit the air screen to the rim around the edge of the bellmouth. I will save the last touch until I have the engine put together and can cut the notch for the oil feed in the rim. I might powder coat it black or something later.  It is not a perfect radius since I have to keep it axially short in order to fit an air screen with as large area as possible in the bike chassis. Still leagues better flowing than the old one, it might cure the high pitched whistle I got from the compressor at high rpms.  Cheers! /Anders |
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Post by azwood on Jan 5, 2019 5:06:14 GMT -5
Does anyone know what radial clearance I’d need on my power turbine and how much clearance off the back wall I was thinking 1.5mm radiel and 1mm at the back.
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Post by azwood on Jan 5, 2019 6:25:44 GMT -5
Some progress with the intake bellmouth, I will fit the air screen to the rim around the edge of the bellmouth. I will save the last touch until I have the engine put together and can cut the notch for the oil feed in the rim. I might powder coat it black or something later. It is not a perfect radius since I have to keep it axially short in order to fit an air screen with as large area as possible in the bike chassis. Still leagues better flowing than the old one, it might cure the high pitched whistle I got from the compressor at high rpms. Cheers! /Anders I bet that will catch some air at 200+mph nicely done my intake was a strainer from the kitchen lol but hey they work and are easy to find in all sizes |
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Post by turboron on Jan 5, 2019 7:58:49 GMT -5
Aaron, I use a TV84 power turbine for my DIY. It has a relatively tight radial clearance at the inducer. Lesson learned is that the tight clearance causes a rotor lockup at startup since the rotor heats up faster than the housing. After a few minutes it will unlock at the higher power settings. I will look up the numbers today if I have time. You lose about 1% in efficiency for each thousandth of clearance. Efficiency is not an issue for us unless it gets excessive.
Thanks, Ron
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wishing every luck 
